CAPE CANAVERAL, Fla. — California-based SpaceX said it conducted a successful engine test for its Falcon 9 launch vehicle on Saturday, marking a key milestone on the way to the inaugural launch of a commercial rocket that President Barack Obama hopes will one day ferry astronauts to the International Space Station.

The 18-story Falcon 9 was anchored to its launch pad at Cape Canaveral Air Force Station when its nine engines burned to full thrust for 3.5 seconds.

"All appeared normal at first glance," said Elon Musk, the millionaire founder of SpaceX, also known as Space Exploration Technologies Corp.

The first attempt to carry out the test was aborted on Tuesday just as the engines were about to fire up. The abort was attributed to a problem with ground support equipment rather than the rocket itself.

With the success of Saturday's "hot fire" test, the Falcon 9 could lift off for the first time as early as April 12.

SpaceX holds a $1.6 billion NASA contract to launch 15 Falcon 9 flights — including three flight tests and 12 missions to deliver cargo to the space station. SpaceX could eventually be called upon to ferry astronauts to the orbiting outpost as well.

The California-based company also holds contracts to launch commercial payloads for customers in Argentina, Canada, Europe, Israel and the United States.

The Obama White House's revised vision for space exploration, released last month, called for a greater reliance on commercial launch providers such as SpaceX. It also canceled NASA's program to develop a new rocket known as the Ares 1. The program was part of the space agency's Constellation program to send astronauts back to the moon.

Members of Congress hope to revive some elements of the Constellation effort, even though NASA's back-to-the-moon plan has been put on hold.

Obama is due to participate in a space policy summit in Florida on April 15 that should help flesh out his revised vision for space exploration. Among other things, the meeting may refocus America's longer-term aspirations on Mars rather than the moon.

This report includes information from NBC News' Jay Barbree in Cape Canaveral.